Method of testing the operation of an apparatus for detecting acceleration

Abstract

A fixed substrate (10) having rigidity and a flexible substrate (20) having flexibility are arranged in such a manner that they are opposite to each other. Both the substrates are fixed at their peripheral portions by a detector casing (40). A working body (30) is connected onto the lower surface of the flexible substrate. Test electrodes (11t, 13t, 15t) are formed on the lower surface of the fixed substrate, and fixed electrodes (11, 13, 15) are further formed through an insulating layer (16). Displacement electrodes (21, 23, 25) are formed on the upper surface of the flexible substrate. When an acceleration is exerted on the working body, the flexible substrate is bent, so the distance between the fixed electrode and the displacement electrode is varied. By detecting the change of distance as a change of the electrostatic capacitance between both the electrodes, it is possible to detect an acceleration exerted. In order to carry out the operation test of this detector, a voltage is applied across the test electrode and the displacement electrode, thus allowing coulomb force to be exerted between both the electrodes. Thus, the flexible substrate is bent by coulomb force, resulting in the same state as the state where an acceleration is exerted. By examining a change of the electrostatic capacitance between the fixed electrode and the displacement electrode, the operation test can be conducted.

I claim: 
     
       1. An acceleration sensor to detect a first component of acceleration along an X-axis and a second component of acceleration along a Y-axis in an XYZ three-dimensional coordinate system, the sensor comprising: a sensor casing;   a flexible substrate arranged parallel with an XY-plane of said coordinate system, said flexible substrate including a working portion to which a force is applied, a fixed portion fixed to said sensor casing, and a flexible portion having flexibility located between said working portion and said fixed portion;   a fixed substrate arranged parallel with the XY-plane so as to face to said flexible substrate with a predetermined distance and fixed to said sensor casing;   a working body attached to said working portion to transmit a force produced by an acceleration to said working portion so that said flexible substrate produces mechanical deformation;   four capacitance elements, each of said capacitance elements being comprised of a displacement electrode fixed to said flexible substrate on a first plane parallel with the XY-plane and a fixed electrode fixed to said fixed substrate on a second plane parallel with the XY-plane, each displacement electrode facing each fixed electrode, the respective electrodes of at least one of the four displacement electrodes and the four fixed electrodes being insulated from each other so that said four capacitance elements are electrically independent from each other, wherein a first capacitance element is located in a positive sector of the X-axis, a second capacitance element is located in a negative sector of the X-axis, a third capacitance element is located in a positive sector of the Y-axis and a fourth capacitance element is located in a negative sector of the Y-axis;   four test electrodes fixed to said fixed substrate on a third plane parallel with the XY-plane, said test electrodes being isolated from each other and from the fixed electrodes, and each of said four test electrodes facing each of the four displacement electrodes;   detection means for detecting the first component of acceleration along the X-axis based on a change of an electrostatic capacitance in the first capacitance element and the second capacitance element and for detecting the second component of acceleration along the Y-axis based on a change of an electrostatic capacitance in the third capacitance element and the fourth capacitance element; and   voltage application means for applying a predetermined voltage across a test electrode and a displacement electrode facing thereto for moving the displacement electrode by a coulomb force so that the flexible substrate produces mechanical deformation.   
     
     
       2. An acceleration sensor to detect a first component of acceleration along an X-axis, a second component of acceleration along a Y-axis, and a third component of acceleration along a Z-axis in an XYZ three-dimensional coordinate system, the sensor comprising: a sensor casing;   a flexible substrate arranged parallel with an XY-plane of said, coordinate system, said flexible substrate including a working portion to which a force is applied, a fixed portion fixed to said sensor casing, and a flexible portion having flexibility located between said working portion and said fixed portion;   a fixed substrate arranged parallel with the XY-plane so as to face said flexible substrate with a predetermined distance and fixed to said sensor casing;   a working body attached to said working portion to transmit a force produced by an acceleration to said working portion so that said flexible substrate produces mechanical deformation;   five capacitance elements, each of said capacitance elements being comprised of a displacement electrode fixed to said flexible substrate on a first plane parallel with the XY-plane and a fixed electrode fixed to said fixed substrate on a second plane parallel with the XY-plane, each displacement electrode facing each fixed electrode,   the respective electrodes of at least one of the five displacement electrodes and the five fixed electrodes being insulated from each other so that said five capacitance elements are electrically independent from each other, wherein a first capacitance element is located in a positive sector of the X-axis, a second capacitance element is located in a negative sector of the X-axis, a third capacitance element is located in a positive sector of the Y-axis, a fourth capacitance element is located in a negative sector of the Y-axis, and a fifth capacitance element is located so as to cross the Z-axis;   five test electrodes fixed to said fixed substrate on a third plane parallel with the XY-plane, said test electrodes being isolated from each other and from the fixed electrodes, and each of said five test electrodes facing each of the five displacement electrodes;   detection means for detecting the first component of acceleration along the X-axis based on a change of an electrostatic capacitance in the first capacitance element and the second capacitance element, for detecting the second component of acceleration along the Y-axis based on a change of an electrostatic capacitance in the third capacitance element and the fourth capacitance element, and for detecting the third component of acceleration along the Z-axis based on a change of an electrostatic capacitance in the fifth capacitance element; and   voltage application means for applying a predetermined voltage across a test electrode and a displacement electrode facing thereto for moving the displacement electrode by a coulomb force so that the flexible substrate produces mechanical deformation.   
     
     
       3. An acceleration sensor to detect a first component of acceleration along an X-axis and a second component of acceleration along a Y-axis in an XYZ three-dimensional coordinate system, the sensor comprising: a sensor casing;   a flexible substrate arranged parallel with an XY-plane of said coordinate system, said flexible substrate including a working portion to which a force is applied, a fixed portion fixed to said sensor casing, and a flexible portion having flexibility located between said working portion and said fixed portion;   a fixed substrate arranged parallel with the XY-plane so as to face to said flexible substrate with a predetermined distance and fixed to said sensor casing;   a working body attached to said working portion to transmit a force produced by an acceleration to said working portion so that said flexible substrate produces mechanical deformation;   four capacitance elements, each of said capacitance elements being comprised of a displacement electrode fixed to said flexible substrate on a first plane parallel with the XY-plane and a fixed electrode fixed to said fixed substrate on a second plane parallel with the XY-plane, each displacement electrode facing each fixed electrode, respective electrodes of at least one of the four displacement electrodes and the four fixed electrodes being insulated from each other so that said four capacitance elements are electrically independent from each other, wherein a first capacitance element is located in a positive sector of the X-axis, a second capacitance element is located in a negative sector of the X-axis, a third capacitance element is located in a positive sector of the Y-axis and a fourth capacitance element is located in a negative sector of the Y-axis;   four test electrodes fixed to said flexible substrate on a third plane parallel with the XY-plane, said test electrodes being isolated from each other and from the displacement electrodes, and each of said four test electrodes facing each of the four fixed electrodes;   detection means for detecting the first component of acceleration along the X-axis based on a change of an electrostatic capacitance in the first capacitance element and the second capacitance element and for detecting the second component of acceleration along the Y-axis based on a change of an electrostatic capacitance in the third capacitance element and the fourth capacitance element; and   voltage application means for applying a predetermined voltage across a test electrode and a fixed electrode facing thereto for moving the test electrode by a coulomb force so that the flexible substrate produces mechanical deformation.   
     
     
       4. An acceleration sensor to detect a first component of acceleration along an X-axis, a second component of acceleration along a Y-axis, and a third component of acceleration along a Z-axis in an XYZ three-dimensional coordinate system, the sensor comprising: a sensor casing;   a flexible substrate arranged parallel with an XY-plane of said coordinate system, said flexible substrate including a working portion to which a force is applied, a fixed portion fixed to said sensor casing, and a flexible portion having flexibility located between said working portion and said fixed portion;   a fixed substrate arranged parallel with the XY-plane so as to face to said flexible substrate with a predetermined distance and fixed to said sensor casing;   a working body attached to said working portion to transmit a force produced by an acceleration to said working portion so that said flexible substrate produces mechanical de formation;   five capacitance elements, each of said capacitance elements being comprised of a displacement electrode fixed to said flexible substrate on a first plane parallel with the XY-plane and a fixed electrode fixed to said fixed substrate on a second plane parallel with the XY-plane, each displacement electrode facing each fixed electrode, the respective electrodes of at least one of the five displacement electrodes and the five fixed electrodes being insulated from each other so that said five capacitance elements are electrically independent from each other, wherein a first capacitance element is located in a positive sector of the X-axis, a second capacitance element is located in a negative sector of the X-axis, a third capacitance element is located in a positive sector of the Y-axis, a fourth capacitance element is located in a negative sector of the Y-axis, and a fifth capacitance element is located so as to cross the Z-axis;   five test electrodes fixed to said flexible substrate on a third plane parallel with the XY-plane, said test electrodes being isolated from each other and from the displacement electrodes, and each of said five test electrodes facing each of the five fixed electrodes;   detection means for detecting the first component of acceleration along the X-axis based on a change of an electrostatic capacitance in the first capacitance element and the second capacitance element, for detecting the second component of acceleration along the Y-axis based on a change of an electrostatic capacitance in the third capacitance element and the fourth capacitance element, and for detecting the third component of acceleration along the Z-axis based on a change of an electrostatic capacitance in the fifth capacitance element; and   voltage application means for applying a predetermined voltage across a test electrode and a fixed electrode facing thereto for moving the test electrode by a coulomb force so that the flexible substrate produces mechanical deformation.   
     
     
       5. An acceleration sensor to detect a first component of acceleration along an X-axis and a second component of acceleration along a Y-axis in an XYZ three-dimensional coordinate system, the sensor comprising: a sensor casing;   a flexible substrate arranged parallel with an XY-plane of said coordinate system, said flexible substrate including a working portion to which a force is applied, a fixed portion fixed to said sensor casing, and a flexible portion having flexibility located between said working portion and said fixed portion;   a fixed substrate arranged parallel with the XY-plane so as to face to said flexible substrate with a predetermined distance and fixed to said sensor casing;   a working body attached to said working portion to transmit a force produced by an acceleration to said working portion so that said flexible substrate produces mechanical deformation;   four capacitance elements, each of said capacitance elements being comprised of a displacement electrode fixed to said flexible substrate on a first plane parallel with the XY-plane and a fixed electrode fixed to said fixed substrate on a second plane parallel with the XY-plane, each displacement electrode facing each fixed electrode, the respective electrodes of at least one of the four displacement electrodes and the four fixed electrodes being insulated from each other so that said four capacitance elements are electrically independent from each other, wherein a first capacitance element is located in a positive sector of the X-axis, a second capacitance element is located in a negative sector of the X-axis, a third capacitance element is located in a positive sector of the Y-axis and a fourth capacitance element is located in a negative sector of the Y-axis;   four fixed test electrodes fixed to said fixed substrate on a third plane parallel with the XY-plane, said fixed test electrodes being isolated from each other and from the fixed electrodes, wherein a first fixed test electrode is located in a positive sector of the X-axis, a second fixed test electrode is located in a negative sector of the X-axis, a third fixed test electrode is located in a positive sector of the Y-axis, and a fourth fixed test electrode is located in a negative sector of the Y-axis;   four displacement test electrodes fixed to said flexible substrate on a fourth plane parallel with the XY-plane, said displacement test electrodes being isolated from each other and from the displacement electrodes, and each of said displacement test electrodes facing each of the four fixed test electrodes;   detection means for detecting the first component of acceleration along the X-axis based on a change of an electrostatic capacitance in the first capacitance element and the second capacitance element and for detecting the second component of acceleration along the Y-axis based on a change of an electrostatic capacitance in the third capacitance element and the fourth capacitance element; and   voltage application means for applying a predetermined voltage across a fixed test electrode and a displacement test electrode facing thereto for moving the displacement test electrode by a coulomb force so that the flexible substrate produces mechanical deformation.   
     
     
       6. An acceleration sensor to detect a first component of acceleration along an X-axis, a second component of acceleration along a Y-axis, and a third component of acceleration along a Z-axis in an XYZ three-dimensional coordinate system, the sensor comprising: a sensor casing;   a flexible substrate arranged parallel with an XY-plane of said coordinate system, said flexible substrate including a working portion to which a force is applied, a fixed portion fixed to said sensor casing, and a flexible portion having flexibility located between said working portion and said fixed portion;   a fixed substrate arranged parallel with the XY-plane so as to face said flexible substrate with a predetermined distance and fixed to said sensor casing;   a working body attached to said working portion to transmit a force produced by an acceleration to said working portion so that said flexible substrate produces mechanical deformation;   five capacitance elements, each of said capacitance elements being comprised of a displacement electrode fixed to said flexible substrate on a first plane parallel with the XY-plane and a fixed electrode fixed to said fixed substrate on a second plane parallel with the XY-plane, each displacement electrode facing each fixed electrode, the respective electrodes of at least one of the five displacement electrodes and the five fixed electrodes being insulated from each other so that said five capacitance elements are electrically independent from each other, wherein a first capacitance element is located in a positive sector of the X-axis, a second capacitance element is located in a negative sector of the X-axis, a third capacitance element is located in a positive sector of the Y-axis, a fourth capacitance element is located in a negative sector of the Y-axis, and a fifth capacitance element is located so as to cross the Z-axis;   five fixed test electrodes fixed to said fixed substrate on a third plane parallel with the XY-plane, said fixed test electrodes being isolated from each other and from the fixed electrodes, wherein a first fixed test electrode is located in a positive sector of the X-axis, a second fixed test electrode is located in a negative sector of the X-axis, a third fixed test electrode is located in a positive sector of the Y-axis, a fourth fixed test electrode is located in a negative sector of the Y-axis, and a fifth fixed test electrode is located so as to cross the Z-axis;   five displacement test electrodes fixed to said flexible substrate on a fourth plane parallel with the XY-plane, said displacement test electrodes being isolated from each other and from the displacement electrodes, and each of said displacement test electrodes facing each of the five fixed test electrodes;   detection means for detecting the first component of acceleration along the X-axis based on a change of an electrostatic capacitance in the first capacitance element and the second capacitance element, for detecting the second component of acceleration along the Y-axis based on a change of an electrostatic capacitance in the third capacitance element and the fourth capacitance element, and for detecting the third component of acceleration along the Z-axis based on a change of an electrostatic capacitance in the fifth capacitance element; and   voltage application means for applying a predetermined voltage across a fixed test electrode, and a displacement test electrode facing thereto for moving the displacement test electrode by a coulomb force so that the flexible substrate produces mechanical deformation.   
     
     
       7. A method of testing an operation of an acceleration sensor to detect a first component of acceleration along an X-axis and a second component of acceleration along a Y-axis in an XYZ three-dimensional coordinate system, said method comprising: providing a sensor having;   a sensor casing;   a flexible substrate arranged parallel with an XY-plane of said coordinate system, said flexible substrate including a working portion to which a force is applied, a fixed portion fixed to said sensor casing, and a flexible portion having flexibility located between said working portion and said fixed portion;   a fixed substrate arranged parallel with the XY-plane so as to face said flexible substrate with a predetermined distance and fixed to said sensor casing;   a working body attached to said working portion to transmit a force produced by an acceleration to said working portion so that said flexible substrate produces mechanical deformation;   four capacitance elements, each of said capacitance elements being comprised of a displacement electrode fixed to said flexible substrate on a first plane parallel with the XY-plane and a fixed electrode fixed to said fixed substrate on a second plane parallel with the XY-plane, each displacement electrode facing each fixed electrode, the respective electrodes of at least one of the four displacement electrodes and the four fixed electrodes being insulated from each other so that said four capacitance elements are electrically independent from each other, wherein a first capacitance element is located in a positive sector of the X-axis, a second capacitance element is located in a negative sector of the X-axis, a third capacitance element is located in a positive sector of the Y-axis and a fourth capacitance element is located in a negative sector of the Y-axis; and   detection means for detecting the first component of acceleration along the X-axis based on a change of an electrostatic capacitance in the first capacitance element and the second capacitance element and for detecting the second component of acceleration along the Y-axis based on a change of an electrostatic capacitance in the third capacitance element and the fourth capacitance element;   said method comprising the steps of:   applying a predetermined voltage across a fixed electrode and a displacement electrode facing thereto for moving the displacement electrode by a coulomb force so that the flexible substrate produces mechanical deformation, and   detecting an output from said detection means while said predetermined voltage is applied.   
     
     
       8. A method of testing an operation of an acceleration sensor to detect a first component of acceleration along an X-axis, a second component of acceleration along a Y-axis, and a third component of acceleration along a Z-axis in an XYZ three-dimensional coordinate system, said method comprising: providing a sensor having;   a sensor casing;   a flexible substrate arranged parallel with an XY-plane of said coordinate system, said flexible substrate including a working portion to which a force is applied, a fixed portion fixed to said sensor casing, and a flexible portion having flexibility located between said working portion and said fixed portion;   a fixed substrate arranged parallel with the XY-plane so as to face said flexible substrate with a predetermined distance and fixed to said sensor casing;   a working body attached to said working portion to transmit a force produced by an acceleration to said working portion so that said flexible substrate produces mechanical deformation;   five capacitance elements, each of said capacitance elements being comprised of a displacement electrode fixed to said flexible substrate on a first plane parallel with the XY-plane and a fixed electrode fixed to said fixed substrate on a second plane parallel with the XY-plane, each displacement electrode facing each fixed electrode, the respective electrodes of at least one of the five displacement electrodes and the five fixed electrodes being insulated from each other so that said five capacitance elements are electrically independent from each other, wherein a first capacitance element is located in a positive sector of the X-axis, a second capacitance element is located in a negative sector of the X-axis, a third capacitance element is located in a positive sector of the Y-axis, a fourth capacitance element is located in a negative sector of the Y-axis, and a fifth capacitance element is located so as to cross the Z-axis; and   detection means for detecting the first component of acceleration along the X-axis based on a change of an electrostatic capacitance in the first capacitance element and the second capacitance element, and for detecting the second component of acceleration along the Y-axis based on a change of an electrostatic capacitance in the third capacitance element and the fourth capacitance element, and for detecting the third component of acceleration along the Z-axis based on a change of an electrostatic capacitance in the fifth capacitance element;   said method further comprising:   applying a predetermined voltage across a fixed electrode and a displacement electrode facing thereto for moving the displacement electrode by a coulomb force so that the flexible substrate produces mechanical deformation, and   detecting an output from said detection means while said predetermined voltage is applied.   
     
     
       9. A method of testing an operation of an acceleration sensor to detect a first component of acceleration along an X-axis, a second component of acceleration along a Y-axis in an XYZ three-dimensional coordinate system, said method comprising: providing a sensor having;   a sensor casing;   a flexible substrate arranged parallel with an XY-plane of said coordinate system, said flexible substrate including a working a portion to which a force is applied, a fixed portion fixed to said sensor casing, and a flexible portion having flexibility located between said working portion and said fixed portion;   a fixed substrate arranged parallel with the XY-plane so as to face said flexible substrate with a predetermined distance and fixed to said sensor casing;   a working body attached to said working portion to transmit a force produced by an acceleration to said working portion so that said flexible substrate produces mechanical deformation;   four capacitance elements, each of said capacitance elements being comprised of a displacement electrode fixed to said flexible substrate on a first plane parallel with the XY-plane and a fixed electrode fixed to said fixed substrate on a second plane parallel with the XY-plane, each displacement electrode facing each fixed electrode, respective electrodes of at least one of the four displacement electrodes and the four fixed electrodes being insulated from each other so that said four capacitance elements are electrically independent from each other, wherein a first capacitance element is located in a positive sector of the X-axis, a second capacitance element is located in a negative sector of the X-axis, a third capacitance element is located in a positive sector of the Y-axis, and a fourth capacitance element is located in a negative sector of the Y-axis; and   detection means for detecting the first component of acceleration along the X-axis based on a change of an electrostatic capacitance in the first capacitance element and the second capacitance element and for detecting the second component of acceleration along the Y-axis based on a change of an electrostatic capacitance in the third capacitance element and the fourth capacitance element;   said method further comprising:   providing a test electrode fixed to said fixed substrate on a third plane parallel with the XY-plane, said test electrode being isolated from the fixed electrodes, and said test electrode facing one of the four displacement electrodes;   applying a predetermined voltage across said test electrode and a displacement electrode facing thereto for moving the displacement electrode by a coulomb force so that the flexible substrate produces mechanical deformation, and   detecting an output from said detection means while said predetermined voltage is applied.   
     
     
       10. A method of testing an acceleration sensor to detect a first component of acceleration along an X-axis, a second component of acceleration along a Y-axis, and a third component of acceleration along a Z-axis in an XYZ three-dimensional coordinate system, said method comprising: providing a sensor having;   a sensor casing;   a flexible substrate arranged parallel with an XY-plane of said coordinate system, said flexible substrate including a working portion to which a force is applied, a fixed portion fixed to said sensor casing, and a flexible portion having flexibility located between said working portion and said fixed portion;   a fixed substrate arranged parallel with the XY-plane so as to face said flexible substrate with a predetermined distance and fixed to said sensor casing;   a working body attached to said working portion to transmit a force produced by an acceleration to said working portion so that said flexible substrate produces mechanical deformation;   five capacitance elements, each of said capacitance elements being comprised of a displacement electrode fixed to said flexible substrate on a first plane parallel with the XY-plane and a fixed electrode fixed to said fixed substrate on a second plane parallel with the XY-plane, each displacement electrode facing each fixed electrode, respective electrodes of at least one of the five displacement electrodes and the five fixed electrodes being insulated from each other so that said five capacitance elements are electrically independent from each other, wherein a first capacitance element is located in a positive sector of the X-axis, a second capacitance element is located in a negative sector of the X-axis, a third capacitance element is located in a positive sector of the Y-axis, a fourth capacitance element is located in a negative sector of the Y-axis, and a fifth capacitance element is located so as to cross the Z-axis; and   detection means for detecting the first component of acceleration along the X-axis based on a change of an electrostatic capacitance in the first capacitance element and the second capacitance element, for detecting the second component of acceleration along the Y-axis based on a change of an electrostatic capacitance in the third capacitance element and the fourth capacitance element, and for detecting the third component of acceleration along the Z-axis based on a change of electrostatic capacitance in the fifth capacitance element;   said method further comprising:   providing a test electrode fixed to said fixed substrate on a third plane parallel with the XY-plane, said test electrode being isolated from the fixed electrodes, and said test electrode facing one of the four displacement electrodes;   applying a predetermined voltage across said test electrode and a displacement electrode facing thereto for moving the displacement electrode by a coulomb force so that the flexible substrate produces mechanical deformation, and   detecting an output from said detection means while said predetermined voltage is applied.   
     
     
       11. A method of testing an acceleration sensor to detect a first component of acceleration along an X-axis, a second component of acceleration along a Y-axis in an XYZ three-dimensional coordinate system, said method comprising: providing a sensor having;   a sensor casing;   a flexible substrate arranged parallel with an XY-plane of said coordinate system, said flexible substrate including a working portion to which a force is applied, a fixed portion fixed to said sensor casing, and a flexible portion having flexibility located between said working portion and said fixed portion;   a fixed substrate arranged parallel with the XY-plane so as to face said flexible substrate with a predetermined distance and fixed to said sensor casing;   a working body attached to said working portion to transmit a force produced by an acceleration to said working portion so that said flexible substrate produces mechanical deformation;   four capacitance elements, each of said capacitance elements being comprised of a displacement electrode fixed to said flexible substrate on a first plane parallel with the XY-plane and a fixed electrode fixed to said fixed substrate on a second plane parallel with the XY-plane, each displacement electrode facing each fixed electrode, the respective electrodes of at least one of the four displacement electrodes and the four fixed electrodes being insulated from each other so that said four capacitance elements are electrically independent from each other, wherein a first capacitance element is located in a positive sector of the X-axis, a second capacitance element is located in a negative sector of the X-axis, a third capacitance element is located in a positive sector of the Y-axis and a fourth capacitance element is located in a negative sector of the Y-axis; and   detection means for detecting the first component of acceleration along the X-axis based on a change of an electrostatic capacitance in the first capacitance element and the second capacitance element and for detecting the second component of acceleration along the Y-axis based on a change of an electrostatic capacitance in the third capacitance element and the fourth capacitance element; and   said method further comprising:   providing a test electrode fixed to said flexible substrate on a third plane parallel with the XY-plane, said test electrode being isolated from the displacement electrodes, and said test electrode facing one of the four fixed electrodes;   applying a predetermined voltage across said test electrode and a fixed electrode facing thereto for moving the test electrode by a coulomb force so that the flexible substrate produces mechanical deformation; and   detecting an output from said detection means while said predetermined voltage is applied.   
     
     
       12. A method of testing an acceleration sensor to detect a first component of acceleration along an X-axis, a second component of acceleration along a Y-axis, and a third component of acceleration along a Z-axis in an XYZ three-dimensional coordinate system, said method comprising: providing a sensor having;   a sensor casing;   a flexible substrate arranged parallel with an XY-plane of said coordinate system, said flexible substrate including a working portion to which a force is applied, a fixed portion fixed to said sensor casing, and a flexible portion having flexibility located between said working portion and said fixed portion;   a fixed substrate arranged parallel with the XY-plane so as to face said flexible substrate with a predetermined distance and fixed to said sensor casing;   a working body attached to said working portion to transmit a force produced by an acceleration to said working portion so that said flexible substrate produces mechanical deformation;   five capacitance elements, each of said capacitance elements being comprised of a displacement electrode fixed to said flexible substrate on a first plane parallel with the XY-plane and a fixed electrode fixed to said fixed substrate on a second plane parallel with the XY-plane, each displacement electrode facing each fixed electrode, the respective electrodes of at least one of the five displacement electrodes and the five fixed electrodes being insulated from each other so that said five capacitance elements are electrically independent from each other, wherein a first capacitance element is located in a positive sector of the X-axis, a second capacitance element is located in a negative sector of the X-axis, a third capacitance element is located in a positive sector of the Y-axis, a fourth capacitance element is located in a negative sector of the Y-axis, and a fifth capacitance element is located so as to cross the Z-axis; and   detection means for detecting the first component of acceleration along the X-axis based on a change of an electrostatic capacitance in the first capacitance element and the second capacitance element, for detecting the second component of acceleration along the Y-axis based on a change of an electrostatic capacitance in the third capacitance element and the fourth capacitance element, and for detecting the third component of acceleration along the Z-axis based on a change of an electrostatic capacitance in the fifth capacitance element;   said method further comprising:   providing a test electrode fixed to said flexible substrate on a third plane parallel with the XY-plane, said test electrode being isolated from the displacement electrodes, and said test electrode facing one of the five fixed electrodes;   applying a predetermined voltage across said test electrode and a fixed electrode facing thereto for moving the test electrode by a coulomb force so that the flexible substrate produces mechanical deformation; and   detecting an output from said detection means while said predetermined voltage is applied.   
     
     
       13. A method of testing an acceleration sensor to detect a first component of acceleration along an X-axis and a second component of acceleration along a Y-axis in an XYZ three-dimensional coordinate system, said method comprising: providing a sensor having;   a sensor casing;   a flexible substrate arranged parallel with an XY-plane of said coordinate system, said flexible substrate including a working portion to which a force is applied, a fixed portion fixed to said sensor casing, and a flexible portion having flexibility located between said working portion and said fixed portion;   a fixed substrate arranged parallel with the XY-plane so as to face said flexible substrate with a predetermined distance and fixed to said sensor casing;   a working body attached to said working portion to transmit a force produced by an acceleration to said working portion so that said flexible substrate produces mechanical deformation;   four capacitance elements, each of said capacitance elements being comprised of a displacement electrode fixed to said flexible substrate on a first plane parallel with the XY-plane and a fixed electrode fixed to said fixed substrate on a second plane parallel with the XY-plane, each displacement electrode facing each fixed electrode, and the respective electrodes of at least one of the four displacement electrodes and the four fixed electrodes being insulated from each other so that said four capacitance elements are electrically independent from each other, wherein a first capacitance element is located in a positive sector of the X-axis, a second capacitance element is located in a negative sector of the X-axis, a third capacitance element is located in a positive sector of the Y-axis and a fourth capacitance element is located in a negative sector of the Y-axis; and   detection means for detecting the first component of acceleration along the X-axis based on a change of an electrostatic capacitance in the first capacitance element and the second capacitance element and for detecting the second component of acceleration along the Y-axis based on a change of an electrostatic capacitance in the third capacitance element and the fourth capacitance element; and   said method further comprising:   providing a fixed test electrode fixed to said fixed substrate on a third plane parallel with the XY-plane, said fixed test electrode being isolated from the fixed electrodes;   providing a displacement test electrode to said substrate on a fourth plane parallel with the XY-plane, said displacement test electrode being isolated from the displacement electrodes, and said displacement test electrode facing said fixed test electrode;   applying a predetermined voltage across said fixed test electrode and said displacement test electrode facing thereto for moving said displacement test electrode by a coulomb force so that the flexible substrate produces mechanical deformation; and   detecting an output from said detection means while said predetermined voltage is applied.   
     
     
       14. A method of testing an acceleration sensor to detect a first component of acceleration along an X-axis, a second component of acceleration along a Y-axis, and a third component of acceleration along a Z-axis in an XYZ three-dimensional coordinate system, said method comprising: providing a sensor having;   a sensor casing;   a flexible substrate arranged parallel with an XY-plane of said coordinate system, said flexible substrate including a working portion to which a force is applied, a fixed portion fixed to said sensor casing, and a flexible portion having flexibility located between said working portion and said fixed portion;   a fixed substrate arranged parallel with the XY-plane so as to face said flexible substrate with a predetermined distance and fixed to said sensor casing;   a working body attached to said working portion to transmit a force produced by an acceleration to said working portion so that said flexible substrate produces mechanical deformation;   five capacitance elements, each of said capacitance elements being comprised of a displacement electrode fixed to said flexible substrate on a first plane parallel with the XY-plane and a fixed electrode fixed to said fixed substrate on second plane parallel with the XY-plane, each displacement electrode facing each fixed electrode, the respective electrodes of at least one of the five displacement electrodes and the five fixed electrodes being insulated from each other so that said five capacitance elements are electrically independent from each other, wherein a first capacitance element is located in a positive sector of the X-axis, a second capacitance element is located in a negative sector of the X-axis, a third capacitance element is located in a positive sector of the Y-axis, a fourth capacitance element is located in a negative sector of the Y-axis, and a fifth capacitance element is located so as to cross the Z-axis; and   detection means for detecting the first component of acceleration along the X-axis based on a change of an electrostatic capacitance in the first capacitance element and the second capacitance element, for detecting the second component of acceleration along the Y-axis based on a change of an electrostatic capacitance in the third capacitance element and the fourth capacitance element, and for detecting the third component of acceleration along the Z-axis based on a change of an electrostatic capacitance in the fifth capacitance element; and   said method further comprising:   providing a fixed test electrode fixed to said fixed substrate on a third plane parallel with the XY-plane, said fixed test electrode being isolated from the fixed electrodes;   providing a displacement test electrode fixed to said flexible substrate on a fourth plane parallel with the XY-plane, said displacement test electrode being isolated from the displacement electrodes, and said displacement test electrode facing said fixed test electrode;   applying a predetermined voltage across said fixed test electrode and said displacement test electrode facing thereto for moving said displacement test electrode by a coulomb force so that the flexible substrate produces mechanical deformation; and   detecting an output from said detection means while said predetermined voltage is applied.